Abstract Detail

A New Species of Agave (Agavaceae) found with “Rock Piles Galore” in pre-Columbian Agricultural Fields along the San Pedro River, Arizona.

On terraces along the ca. 60 miles of bajada above the San Pedro River floodplain between Benson and Mammoth, Arizona, archeologists have documented tens of thousands of acres of pre-Columbian agricultural sites consisting of rock-pile fields and non-architectural linear rock-pile features. Evidence from previous archeological work in the region suggests that these types of fields were used to cultivate agaves, which were used by Native Americans for food, fiber and beverage. Fortuitously, there are a few locations in which agaves can still be found growing within these fields today. These agaves are only associated with these agricultural features and are not found in the surrounding unmodified settings. Furthermore, they produce very little seed, reproduce readily via vegetative means, and we cannot assign these plants to any described species by morphology or molecular data. Therefore, we propose that these plants represent a putative pre-Columbian domesticate that was cultivated by the Hohokam people. Evidence suggests that the peak interval of agave cultivation in this area was from ca. A.D. 1000 to 1275 and that the impressive scope of the agricultural fields indicate that agaves were important in the Hohokam economy. The limited number of remnant agaves surviving in these field today raises concern for the conservation of this hidden domesticate without renewed human cultivation.